Head suspension assembly and disk device

Abstract

The embodiment provides a head suspension assembly and a disk device with improved connection reliability. According to the embodiment, the head suspension assembly includes a support plate, a wiring member (40) arranged on the support plate, a head mounted on the wiring member, and a retractable piezoelectric element (50) mounted on the wiring member. The wiring member includes a metal plate (44a) fixed to the support plate and a stacked member having a first insulating layer (44b), a conductive layer (44c) stacked on the first insulating layer, a second insulating layer (44d) stacked on the conductive layer, and at least a pair of connecting pads (70a, 70b) formed by the conductive layer. The connecting pad is overlapped and arranged on a recessed portion (74a) formed on the first insulating layer to form a recessed portion along the recessed portion, and the covering insulating layer has an opening (72a) opposite to the connecting pad. The piezoelectric element is connected to the connecting pad by a conductive adhesive (Ad) filled in the opening and the recessed portion of the connecting pad.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2020-148988 (filing date: September 4, 2020), and the present application incorporates the entire contents of the basic application by reference. Technical Field

[0002] Embodiments of the present invention relate to a head suspension assembly and a disk device including the head suspension assembly. Background Art

[0003] As a disk device, for example, a hard disk drive (HDD) includes: a plurality of magnetic disks rotatably arranged in a housing, a plurality of magnetic heads for reading and writing information on the magnetic disks, and a head actuator for supporting the magnetic heads so as to be movable relative to the magnetic disks.

[0004] The head actuator has a plurality of head suspension assemblies supporting the magnetic head at the front end. The head suspension assembly has a substrate having one end fixed to an arm, a load beam extending from the substrate, and a flexure (wiring member) disposed on the load beam and the substrate. The flexure has a freely displaceable universal joint portion, and the magnetic head is supported on the universal joint portion.

[0005] In recent years, a head suspension assembly having a piezoelectric element constituting a microactuator has been proposed. The piezoelectric element is mounted on a flexure. The electrodes of the piezoelectric element are electrically and mechanically connected to a conductor pattern, such as a conductive pad, of the flexure, for example, by a conductive adhesive.

[0006] In the above HDD, the piezoelectric element is placed on the conductive adhesive applied to the flexure, and is bonded to the conductive pad by heating and melting the conductive adhesive. In order to ensure bonding strength and conductivity, the adhesive needs to be applied in a manner that avoids insufficient application. On the other hand, if applied excessively, it will wet and spread, which may cause electrical short circuits and mechanical effects. In this case, the head suspension assembly is treated as a defective product. Summary of the invention

[0007] Embodiments of the present invention provide a head suspension assembly and a disk device having high connection strength of a piezoelectric element and improved reliability.

[0008] According to an embodiment, a head suspension assembly includes a support plate, a wiring member disposed on the support plate, a head mounted on the wiring member, and a retractable piezoelectric element mounted on the wiring member. The wiring member includes a metal plate fixed to the support plate and a laminated member having a first insulating layer, a conductive layer stacked on the first insulating layer, a second insulating layer stacked on the conductive layer, at least a pair of connection pads formed by the conductive layer, and a plurality of wirings connected to the connection pads. The connection pads are overlappedly disposed in a recess formed in the first insulating layer to form a recessed portion sunken along the recess, the covering insulating layer has an opening opposite to the connection pad, and the piezoelectric element is connected to the connection pad by a conductive adhesive filled in the opening and the recess of the connection pad. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is an exploded perspective view of the hard disk drive (HDD) according to the first embodiment.

[0010] Figure 2 is a top view of a head suspension assembly of the HDD.

[0011] Figure 3 is a perspective view showing the head suspension assembly.

[0012] Figure 4 It is a plan view showing the front end portion of the head suspension assembly in an enlarged manner.

[0013] Figure 5 It is an exploded perspective view showing a pad portion of a flexure and a piezoelectric element of the head gimbal assembly.

[0014] Figure 6 1 is a plan view showing a pad portion of the flexure and a piezoelectric element.

[0015] Figure 7 It is along Figure 6 A cross-sectional view of the pad portion and the piezoelectric element taken along line AA.

[0016] Figure 8 It is a plan view showing a pad portion and a piezoelectric element of an HDD according to a second embodiment.

[0017] Fig. 9 It is along Figure 8 A cross-sectional view of the pad portion and the piezoelectric element taken along line BB.

[0018] Fig.10 It is a plan view showing a pad portion and a piezoelectric element of an HDD according to a third embodiment.

[0019] Fig.11 It is along Fig.10A cross-sectional view of the pad portion and the piezoelectric element taken along line CC.

[0020] Fig.12 It is a plan view showing a pad portion and a piezoelectric element of an HDD according to a fourth embodiment.

[0021] Fig.13 It is along Fig.12 A cross-sectional view of the pad portion and the piezoelectric element taken along line DD. DETAILED DESCRIPTION

[0022] Hereinafter, a disk device according to an embodiment will be described with reference to the drawings.

[0023] In addition, the disclosure is only an example, and appropriate and easily conceivable changes that maintain the gist of the invention by a person skilled in the art are of course included in the scope of the present invention. In addition, the drawings sometimes schematically show the size and shape of each part compared to the actual form in order to make the description clearer, but this is only an example and does not limit the interpretation of the present invention. In addition, in this specification and each figure, the same reference numerals are given to the same elements as those already described in the figures that have already appeared, and the detailed description is sometimes appropriately omitted.

[0024] (First embodiment)

[0025] A hard disk drive (HDD) according to the first embodiment will be described in detail as the disk device.

[0026] Figure 1 This is an exploded perspective view of the HDD of the first embodiment shown with the cover removed. As shown in the figure, the HDD has a rectangular housing 10. The housing 10 has a rectangular box-shaped base 12 with an open upper surface and a cover (top cover) 14. The base 12 has a rectangular bottom wall 12a and a side wall 12b erected along the periphery of the bottom wall 12a, and is integrally formed from, for example, aluminum. The cover 14 is formed into a rectangular plate shape from, for example, stainless steel. The cover 14 is screwed onto the side wall 12b of the base 12 by a plurality of screws 13, and the upper opening of the base 12 is hermetically sealed.

[0027] A plurality of, for example, five, magnetic disks 18 as disk-shaped recording media and a spindle motor 19 that supports and rotates the magnetic disks 18 are provided in the housing 10. The spindle motor 19 is disposed on the bottom wall 12a.

[0028] Each magnetic disk 18 is formed into a disk shape with a diameter of 95 mm (3.5 inches), for example, and has a magnetic recording layer on its upper surface and / or lower surface. The magnetic disks 18 are coaxially fitted to a hub (not shown) of a spindle motor 19 and clamped by a clamp spring 20 to be fixed to the hub. Thus, the magnetic disks 18 are supported in a state of being positioned parallel to the bottom wall 12a of the base 12. The plurality of magnetic disks 18 are rotated at a predetermined rotation speed by the spindle motor 19.

[0029] In the present embodiment, five magnetic disks 18 are housed in the housing 10 , but the number of magnetic disks 18 is not limited to five and can be increased or decreased.

[0030] A plurality of magnetic heads 17 for recording and reproducing information on a magnetic disk 18 are provided in the housing 10 (see Figure 2 ) and a head actuator 22 for supporting the magnetic heads 17 so that they can move freely relative to the magnetic disk 18. In addition, a voice coil motor (VCM) 24 for rotating and positioning the head actuator 22, a ramp loading mechanism 25 for holding the magnetic heads 17 at an unloading position away from the magnetic disk 18 when the magnetic heads 17 move to the outermost periphery of the magnetic disk 18, and a substrate unit (FPC unit) 21 on which electronic components such as conversion connectors are installed are provided in the housing 10.

[0031] The head actuator 22 includes an actuator block 29 having a bearing unit 28 built therein, a plurality of arms 32 extending from the actuator block 29, and a suspension assembly 30 (sometimes referred to as a head gimbal assembly (HGA)) extending from each arm 32. The magnetic head 17 is supported at the front end of each suspension assembly 30. The head actuator 22 is rotatably supported by a pivot shaft erected on the bottom wall 12a via the bearing unit 28.

[0032] A printed circuit board (not shown) is screwed onto the outer surface of the bottom wall 12 a . The printed circuit board includes a control unit that controls the operation of the spindle motor 19 and controls the operation of the VCM 24 and the magnetic head 17 via the board unit 21 .

[0033] Next, the structure of the suspension assembly 30 will be described in detail.

[0034] Figure 2 is a top view of the suspension assembly. Figure 3 It is a perspective view of the suspension assembly.

[0035] like Figure 2 and Figure 3 As shown, each suspension assembly 30 includes a suspension 34 extending from an arm 32, and a magnetic head 17 is mounted on the front end of the suspension 34. The magnetic head 17 and the suspension assembly 30 supporting the magnetic head 17 are collectively referred to as a head suspension assembly.

[0036] The suspension 34, which functions as a support plate, includes a rectangular base plate 42 formed of a metal plate having a thickness of several hundred micrometers and a thin and long leaf spring-shaped load beam 35 formed of a metal plate having a thickness of several tens of micrometers. The load beam 35 is fixed to the base plate 42 by overlapping its base end with the front end of the base plate 42 and welding multiple locations. The base end of the load beam 35 is formed to have a width substantially equal to that of the base plate 42. A rod-shaped protrusion 46 is protrudingly provided at the front end of the load beam 35.

[0037] The base plate 42 has a circular opening 42a and an annular protrusion 43 located around the opening at its base end. The base plate 42 is fastened to the front end of the arm 32 by fitting the protrusion 43 into a circular rivet hole (not shown) formed on the rivet seat surface of the arm 32 and riveting the protrusion 43. The base end of the base plate 42 can also be fixed to the front end of the arm 32 by laser welding, spot welding or bonding.

[0038] The suspension assembly 30 includes a thin and long belt-shaped flexure (wiring member) 40 for transmitting recording and reproducing signals and driving signals of the piezoelectric element 50, and a pair of piezoelectric elements (for example, PZT elements) 50 mounted on the flexure 40. Figure 2 As shown, the front end side portion 40a of the flexible member 40 is arranged on the load beam 35 and the substrate 42, and the rear half (extension portion) 40b extends outward from the side edge of the substrate 42 and extends along the side edge of the arm 32. The connection end portion 40c located at the front end of the extension portion 40b has a plurality of connection pads 40f. These connection pads 40f are connected to the main FPC of the substrate unit 21 described above.

[0039] The front end of the flexure 40 is located on the front end of the load beam 35, forming a universal joint portion 36 that functions as an elastic support portion. The magnetic head 17 is mounted and fixed on the universal joint portion 36, and is supported by the load beam 35 via the universal joint portion 36. A pair of piezoelectric elements 50 as driving elements are mounted on the universal joint portion 36, and are located on the base end side of the load beam 35 relative to the magnetic head 17.

[0040] Figure 4 It is a plan view showing the front end portion of the suspension assembly 30 in an enlarged manner.

[0041] like Figure 3 and Figure 4As shown, the flexure 40 has a metal thin plate (metal plate) 44a such as stainless steel as a base and a strip-shaped laminated member 41 adhered or fixed to the metal thin plate 44a, forming a thin and long laminated plate. The laminated member 41 has a base insulating layer (first insulating layer) 44b, most of which is fixed to the metal thin plate 44a, a conductive layer (wiring pattern) 44c formed on the base insulating layer 44b and constituting a plurality of signal wirings 45a, drive wirings 45b, and a plurality of connection pads, and a cover insulating layer (second insulating layer) 44d (see FIG. 1 ) covering the conductive layer 44c and laminated on the base insulating layer 44b. Figure 7 As the conductive layer 44c, for example, copper foil can be used. In the front end side portion 40a of the flexure 40, the metal thin plate 44a is adhered or spot-welded at a plurality of welding points to the surface of the load beam 35 and the substrate 42.

[0042] In the universal joint portion 36 of the flexible member 40, the metal sheet 44a has a rectangular tongue portion (support portion) 36a located on the front end side, a substantially rectangular base end portion (base end plate portion) 36b located on the base end side with a space between the tongue portion 36a and the base end portion, a pair of slender outriggers (connecting rod portions) 36c extending from the tongue portion 36a to the base end portion 36b, and a pair of handles (support protrusions) 36f protruding from the two side edges of the tongue portion 36a to its two sides.

[0043] The base end portion 36b is adhered to the surface of the load beam 35, or is fixed to the surface of the load beam 35 by spot welding. The tongue portion 36a is formed into a size and shape capable of carrying the magnetic head 17, for example, formed into a roughly rectangular shape. The tongue portion 36a is configured in a manner that the central axis in its width direction is consistent with the central axis C of the suspension 34. In addition, the approximate center of the tongue portion 36a abuts against a dimple (convex portion) 48 protruding from the front end portion of the load beam 35. The tongue portion 36a is elastically deformed by a pair of outriggers 36c and can be displaced in various directions. Thus, the tongue portion 36a and the magnetic head 17 can flexibly follow the surface changes of the magnetic disk 18 relative to the roll and pitch directions, and maintain a small gap between the surface of the magnetic disk 18 and the magnetic head 17.

[0044] In the universal joint portion 36, a portion of the laminated member 41 of the flexure 40 is divided into two branches and is located on both sides of the central axis C of the suspension 34. The laminated member 41 has a base end portion 47a fixed to the base end portion 36b of the metal thin plate 44a, a front end portion 47b attached to the tongue portion 36a, a pair of strip-shaped first bridge portions 47c extending from the base end portion 47a to the front end portion 47b, and a pair of strip-shaped second bridge portions 47d extending from the base end portion 47a to the middle of the first bridge portion 47c in parallel with the first bridge portion 47c and merging with the first bridge portion 47c. The first bridge portion 47c is located on both sides of the tongue portion 36a in parallel with the outrigger 36c and extends along the longitudinal direction of the load beam 35. In addition, the first bridge portion 47c extends through the handle portion 36f and the crossbar of the outrigger 36c and is partially fixed to them. A portion of each first bridge portion 47 c constitutes a mounting portion 60 to which the piezoelectric element 50 is mounted.

[0045] The magnetic head 17 is fixed to the tongue portion 36a by an adhesive. The magnetic head 17 is arranged so that the central axis in the longitudinal direction is consistent with the central axis of the suspension 34, and the approximate center of the magnetic head 17 is located on the dimple 48. The recording element and the reproducing element of the magnetic head 17 are electrically connected to the plurality of electrode pads 40d of the front end portion 47b by a conductive adhesive such as solder or silver paste. Thus, the magnetic head 17 is connected to the signal wiring 45a via the electrode pads 40d.

[0046] The mounting portion 60 and the piezoelectric element 50 will be described in detail.

[0047] Figure 5 4 is an exploded perspective view showing the mounting portion of the flexure 40 and the piezoelectric element. Figure 6 is a top view of the mounting portion on which the piezoelectric element is mounted. Figure 7 It is along Figure 6 A cross-sectional view of the mounting portion and the piezoelectric element along line AA.

[0048] like Figure 5 As shown, the mounting portion 60 includes a first connection pad 70a and a second connection pad 70b, each formed of a conductive layer 44c. The first connection pad 70a and the second connection pad 70b are respectively connected to the drive wiring 45b formed of the conductive layer 44c. The first connection pad 70a and the second connection pad 70b are arranged at a predetermined interval in a direction parallel to the central axis C of the load beam 35. In this embodiment, the first bridge portion 47c of the flexure 40 is cut off between the first connection pad 70a and the second connection pad 70b. As a result, the first connection pad 70a and the second connection pad 70b are arranged with a space of a predetermined length therebetween.

[0049] like Figure 5 to Figure 7As shown in FIG. 1 , a rectangular recess 74a is formed in the base insulating layer 44b at a position overlapping with the first connection pad 70a. The recess 74a is formed, for example, by half-etching a predetermined portion of the base insulating layer 44b. The recess 74a is formed in a rectangular shape slightly larger than the first connection pad 70a. The first connection pad 70a is formed to overlap the recess 74a, and is recessed along the recess 74a to form a recess.

[0050] A rectangular recess 74b is formed in the base insulating layer 44b at a position overlapping with the second connection pad 70b. The recess 74b is formed, for example, by half-etching a predetermined portion of the base insulating layer 44b. The recess 74b is formed in a rectangular shape slightly larger than the second connection pad 70b. The second connection pad 70b is formed overlappingly on the recess 74a and is recessed along the recess 74a to form a recess.

[0051] The recesses 74a and 74b of the base insulating layer 44b are not limited to being provided in a single connection pad, and a plurality of recesses may be provided in a single connection pad. The shapes of the recesses 74a and 74b are not limited to being rectangular, and various shapes may be selected.

[0052] In the cover insulating layer 44d stacked on the conductive layer 44c, openings 72a and 72b are respectively provided at positions overlapping with the first connection pad 70a and the second connection pad 70b. Most of the first connection pad 70a and most of the second connection pad 70b are exposed on the outer surface of the cover insulating layer 44d through the openings 72a and 72b, respectively. The first connection pad 70a and the second connection pad 70b are respectively formed in a rectangular shape in one example, and similarly, the openings 72a and 72b are formed in a rectangular shape slightly smaller than the connection pads.

[0053] A second covering layer 44e is provided on the covering insulating layer 44d near the opening 72a. The second covering layer 44e is provided on the side of the drive wiring 45b with respect to the opening 72a, that is, on the side opposite to the second connection pad 70b. The second covering layer 44e is formed in a substantially rectangular shape in one example, and extends over substantially the entire width of the first bridge portion 47c. As described later, the second covering layer 44e functions as a dam that restricts the spread of the conductive adhesive.

[0054] Similarly, a second covering layer 44e is provided on the covering insulating layer 44d near the opening 72b. The second covering layer 44e is provided on the side of the drive wiring 45b with respect to the opening 72b, that is, on the side opposite to the first connection pad 70a. The second covering layer 44e is formed in a substantially rectangular shape in one example, and extends over substantially the entire width of the first bridge portion 47c. As described later, the second covering layer 44e functions as a dam that restricts the spread of the conductive adhesive.

[0055] In one example, the second cover layer 44e is formed to have a film thickness substantially the same as that of the cover insulating layer 44d, and is formed of the same insulating material as that of the cover insulating layer 44d. In addition, the second cover layer 44e is not limited to a rectangular shape, and any shape can be selected. The second cover layer 44e can also be provided in a manner slightly away from the openings 72a and 72b.

[0056] The piezoelectric element 50 as a driving element includes, in one example, a piezoelectric body 50a formed of a piezoelectric material in a flat rectangular parallelepiped shape, and a first electrode 51a and a second electrode 51b provided on the outer surface of the piezoelectric body 50a. As the piezoelectric material, for example, zinc zirconate titanate, ceramics, etc. are used.

[0057] The first electrode 51a is provided from one end of the lower surface of the piezoelectric body 50a to the side surface of the short side and most of the upper surface. The second electrode 51b is provided from one end of the upper surface of the piezoelectric body 50a to the side surface of the other short side and most of the lower surface. On the lower surface of the piezoelectric body 50a, one end of the first electrode 51a and one end of the second electrode 51b are opposite to each other with a gap therebetween. On the upper surface of the piezoelectric body 50a, the other end of the first electrode 51a and the other end of the second electrode 51b are opposite to each other with a gap therebetween.

[0058] By applying a voltage between the first electrode 51a and the second electrode 51b, the piezoelectric body 50a sandwiched between the first electrode 51a and the second electrode 51b is extended or contracted in the length direction. In one example, the first electrode 51a is set as a voltage application (Vin) side electrode, and the second electrode 51b is set as a ground (GND) side electrode.

[0059] like Figure 5 to Figure 7 As shown, the piezoelectric element 50 is arranged on the mounting portion 60 in a state where one end portion (the first electrode 51a) of the piezoelectric body 50a in the longitudinal direction is opposite to the first connecting pad 70a and the other end portion (the second electrode 51b) in the longitudinal direction is opposite to the second connecting pad 70b. A conductive adhesive Ad is filled between the first connecting pad 70a and the first electrode 51a. As the conductive adhesive, for example, silver paste, solder, etc. can be used. The first electrode 51a is electrically and mechanically connected to the first connecting pad 70a through the conductive adhesive Ad. At this time, the conductive adhesive Ad is filled into the opening 72a of the covering insulating layer 44d and the recess of the first connecting pad 70a along the recess 74a, and is bonded to the surface of the first connecting pad 70a and the inner surface of the opening 72a (covering the insulating layer 44d). Furthermore, the conductive adhesive Ad is adhered to the edge of the second cover layer 44e and is blocked by the second cover layer 44e to limit leakage to the drive wiring 45b side.

[0060] When the microactuator is operated, a driving voltage is applied to the first electrode 51 a via the driving wiring 45 b , the first connection pad 70 a , and the conductive adhesive Ad.

[0061] Similarly, a conductive adhesive Ad is filled between the second connection pad 70b and the second electrode 51b. The second electrode 51b is electrically and mechanically connected to the second connection pad 70b through the conductive adhesive Ad. At this time, the conductive adhesive Ad is filled into the opening 72b of the cover insulating layer 44d and the recessed part of the second connection pad 70b recessed along the recessed part 74b, and adheres to the surface of the second connection pad 70b and the inner surface of the opening 72b (the first cover insulating layer 44d). In addition, the conductive adhesive Ad is adhered to the edge of the second cover layer 44e, and is blocked by the second cover layer 44e to limit the overflow to the drive wiring 45b side.

[0062] In the HDD configured as described above, by applying a voltage (driving signal) to the piezoelectric element 50 via the driving wiring 45b, the piezoelectric element 50 expands and contracts along its longitudinal direction (a direction parallel to the central axis C of the suspension). Figure 4 As shown by the arrow D, by driving the two piezoelectric elements 50 in opposite directions of expansion and contraction, the pair of first bridge portions 47c also produce strokes in opposite directions. The first bridge portion 47c causes the tongue portion 36a of the universal joint portion 36 and the magnetic head 17 to swing around the dimple 48 in the direction of the arrow D via the handle portion 36f. In this way, the magnetic head 17 can be slightly displaced by the expansion and contraction action of the piezoelectric element 50. In addition, the swing direction D of the magnetic head 17 is equivalent to the seek direction (cross-track direction) of the magnetic head 17 on the magnetic disk 18.

[0063] According to the present embodiment, in the mounting portion 60 of the flexure 40 on which the piezoelectric element 50 is mounted, by forming the first connection pad 70a and the second connection pad 70b in the recessed portions 74a and 74b formed in the base insulating layer 44b and setting the connection pads to a concave shape, the adhesive Ad can be fully accommodated and retained on the connection pads 70a and 70b. Therefore, even in the case where the adhesive Ad is fully applied in a manner to avoid insufficiency in order to ensure the bonding strength and conductivity, the adhesive Ad can be prevented from wetting and spreading to the drive wiring side. At the same time, the contact area between the adhesive Ad and the connection pads 70a and 70b is increased, and a significant anchoring effect brought about by the recessed portions can be obtained. Therefore, the bonding strength of the adhesive Ad relative to the connection pads is further improved.

[0064] Furthermore, according to this embodiment, by providing the second covering layer 44e functioning as a dam on the peripheral portion of the connection pads 70a and 70b, the conductive adhesive Ad can be blocked by the second covering layer 44e and further reliably prevented from leaking toward the drive wiring 45b side. This can eliminate electrical short circuits and mechanical effects caused by the wetting and spreading of the conductive adhesive, and can improve product yield.

[0065] As described above, according to the present embodiment, it is possible to obtain a head gimbal assembly and a disk device in which the connection strength of the piezoelectric element is high and the reliability is improved.

[0066] Next, a head gimbal assembly of an HDD according to another embodiment will be described. In the other embodiments described below, the same reference numerals are given to the same parts as those in the first embodiment, and the detailed description thereof will be omitted or simplified.

[0067] (Second embodiment)

[0068] Figure 8 is a plan view of a mounting portion on which a piezoelectric element is mounted in a head gimbal assembly according to a second embodiment, Fig. 9 It is along Figure 8 A cross-sectional view of the mounting portion and the piezoelectric element along line BB.

[0069] As shown in the figure, in the mounting portion 60 of the flexure 40, the base insulating layer 44b further has a second recess 74c provided near at least one of the first connection pad 70a and the second connection pad 70b. According to the second embodiment, the second recess 74c is provided near the first connection pad 70a on the side of the drive wiring 45b relative to the first connection pad 70a, that is, on the side opposite to the first connection pad 70a. In one example, the second recess 74c is formed in a substantially rectangular shape and is arranged substantially parallel to the recess (first recess) 74a with a gap therebetween. The second recess 74c has a length substantially equal to that of the recess 74a and a width of about half that of the recess 74a. The second recess 74c is formed, for example, by half-etching a predetermined portion of the base insulating layer 44b.

[0070] The second recessed portion 74c of the base insulating layer 44b is not limited to a single one, but may be divided into a plurality of recessed portions. The shape of the second recessed portion 74c is not limited to a rectangular shape, and various shapes may be selected.

[0071] The conductive layer 44c (driving wiring 45b) and the cover insulating layer 44d are formed so as to overlap each other in the second recessed portion 74c, and the overlapping region is recessed along the second recessed portion 74c to form a recessed portion.

[0072] According to the second embodiment, the second covering layer 44e is provided on the covering insulating layer 44d near the second recess 74c. The second covering layer 44e is provided on the side opposite to the first connection pad 70a with respect to the second recess 74c. The second covering layer 44e is formed in a substantially rectangular shape in one example, and extends along one side edge of the second recess 74c and over substantially the entire width of the first bridge portion 47c. The second covering layer 44e functions as a dam that restricts the spread of the conductive adhesive.

[0073] In one example, the second cover layer 44e is formed to have substantially the same film thickness as the cover insulating layer 44d and is formed of the same insulating material as the cover insulating layer 44d. The second cover layer 44e is not limited to a rectangular shape, and any shape may be selected.

[0074] In the mounting portion 60, the recess 74 and the second covering layer 44e on the second connecting pad 70b side have the same structure as the first embodiment described above, but can also be configured such that a second recess is further provided and the second covering layer 44e is provided near the second recess, similarly to the first connecting pad 70a side.

[0075] The piezoelectric element 50 is arranged on the mounting portion 60 in a state where one end portion (the first electrode 51a) of the piezoelectric body 50a in the longitudinal direction is opposite to the first connecting pad 70a and the other end portion (the second electrode 51b) in the longitudinal direction is opposite to the second connecting pad 70b. A conductive adhesive Ad is filled between the first connecting pad 70a and the first electrode 51a. As the conductive adhesive, for example, silver paste, solder, etc. can be used. The first electrode 51a is electrically and mechanically connected to the first connecting pad 70a through the conductive adhesive Ad. At this time, the conductive adhesive Ad is filled into the opening 72a of the covering insulating layer 44d and the recess of the first connecting pad 70a along the recess 74a, and is bonded to the surface of the first connecting pad 70a and the inner surface of the opening 72a (covering the insulating layer 44d). A portion of the conductive adhesive Ad flows on the cover insulating layer 44d and fills the concave portion of the cover insulating layer 44d corresponding to the second concave portion 74c. Furthermore, the conductive adhesive Ad adheres to the edge of the second cover layer 44e and is blocked by the second cover layer 44e to limit leakage to the drive wiring 45b side.

[0076] A conductive adhesive Ad is filled between the second connection pad 70b and the second electrode 51b. The second electrode 51b is electrically and mechanically connected to the second connection pad 70b through the conductive adhesive Ad. At this time, the conductive adhesive Ad is filled into the opening 72b of the cover insulating layer 44d and the recessed part of the second connection pad 70b recessed along the recessed part 74b, and adheres to the surface of the second connection pad 70b and the inner surface of the opening 72b (cover insulating layer 44d). In addition, the conductive adhesive Ad is adhered to the edge of the second cover layer 44e, and is blocked by the second cover layer 44e to limit the overflow to the drive wiring 45b side.

[0077] According to the head suspension assembly of the HDD of the second embodiment configured as described above, in the mounting portion 60 of the flexure 40 to which the piezoelectric element 50 is mounted, by forming the first connection pad 70a and the second connection pad 70b in the recessed portions 74a and 74b formed in the base insulating layer 44b and setting the connection pads to be concave, the adhesive Ad can be fully accommodated and retained on the connection pads 70a and 70b. Therefore, even when the adhesive Ad is fully applied in a manner to avoid insufficiency in order to ensure bonding strength and conductivity, the adhesive Ad can be prevented from wetting and spreading to the drive wiring side. In addition, on the first connection pad 70a side, a part of the conductive adhesive Ad flows on the cover insulating layer 44d and fills the recessed portion of the cover insulating layer 44d corresponding to the second recessed portion 74c. Therefore, even when more conductive adhesive Ad is filled on the first connection pad 70a side, the adhesive Ad can be prevented from wetting and spreading to the drive wiring side. At the same time, the contact area between the adhesive Ad and the connection pads 70a and 70b and the contact area between the adhesive Ad and the cover insulating layer 44d increases, and a significant anchoring effect can be obtained by the recessed portion. Therefore, the bonding strength of the adhesive Ad to the connection pads is further improved.

[0078] Furthermore, according to this embodiment, by providing the second covering layer 44e functioning as a dam on the periphery of the second recess 74c and the periphery of the second connection pad 70b, the conductive adhesive Ad can be blocked by the second covering layer 44e and further reliably prevented from leaking toward the drive wiring 45b side. This can eliminate electrical short circuits and mechanical effects caused by the wetting and spreading of the conductive adhesive, thereby improving product yield.

[0079] As described above, according to the present embodiment, it is possible to obtain a head gimbal assembly and a disk device in which the connection strength of the piezoelectric element is high and the reliability is improved.

[0080] (Third embodiment)

[0081] Fig.10 is a top view of a mounting portion on which a piezoelectric element is mounted in a head gimbal assembly according to a third embodiment. Fig.11 It is along Fig.10 A cross-sectional view of the mounting portion and the piezoelectric element along line CC.

[0082] As shown in the figure, in the mounting portion 60 of the flexure 40, the base insulating layer 44b further has a second recess 74c provided near at least one of the first connection pad 70a and the second connection pad 70b. According to the third embodiment, the second recess 74c is provided near the first connection pad 70a on the side of the drive wiring 45b, i.e., on the opposite side of the second connection pad 70b relative to the first connection pad 70a. In one example, the second recess 74c is formed in a substantially rectangular shape and is arranged substantially parallel to the recess (first recess) 74a with a gap therebetween. The second recess 74c has a length shorter than that of the recess 74a and a width of the same degree as that of the recess 74a. The second recess 74c is formed, for example, by half-etching a predetermined portion of the base insulating layer 44b.

[0083] The second recessed portion 74c of the base insulating layer 44b is not limited to a single one, but may be divided into a plurality of recessed portions. The shape of the second recessed portion 74c is not limited to a rectangular shape, and various shapes may be selected.

[0084] The conductive layer 44c forming the first connection pad 70a and the drive wiring 45b does not overlap with the second recess 74c but is arranged around the second recess 74c. That is, the conductive layer 44c is stacked on the base insulating layer 44b at a position deviated from the second recess 74c. The cover insulating layer 44d is formed overlappingly on the second recess 74c, and the overlapping area is formed with a recess by being recessed along the second recess 74c. In this case, since the conductive layer 44c does not exist in the second recess 74c, the recess formed in the cover insulating layer 44d becomes a recess that is deep according to the film thickness of the conductive layer 44c. In the third embodiment, the second cover layer 44e on the side of the first connection pad 70a is omitted.

[0085] In the mounting portion 60, the recess 74 and the second covering layer 44e on the second connecting pad 70b side have the same structure as the aforementioned first embodiment, but can also be configured such that a second recess 74c is further provided and only the covering insulating layer 44d is formed overlapping the second recess 74c, as is the case with the first connecting pad 70a side.

[0086] The piezoelectric element 50 is arranged on the mounting portion 60 in a state where one end (first electrode 51a) of the piezoelectric body 50a in the longitudinal direction is opposite to the first connection pad 70a and the other end (second electrode 51b) in the longitudinal direction is opposite to the second connection pad 70b. A conductive adhesive Ad is filled between the first connection pad 70a and the first electrode 51a. The first electrode 51a is electrically and mechanically connected to the first connection pad 70a through the conductive adhesive Ad. At this time, the conductive adhesive Ad is filled into the opening 72a of the cover insulating layer 44d and the recess of the first connection pad 70a along the recess 74a, and adheres to the surface of the first connection pad 70a and the inner surface of the opening 72a (cover insulating layer 44d). A part of the conductive adhesive Ad flows on the cover insulating layer 44d and fills into the recess of the cover insulating layer 44d corresponding to the second recess 74c.

[0087] A conductive adhesive Ad is filled between the second connection pad 70b and the second electrode 51b. The second electrode 51b is electrically and mechanically connected to the second connection pad 70b through the conductive adhesive Ad. The conductive adhesive Ad is filled into the opening 72b of the cover insulating layer 44d and the recessed portion of the second connection pad 70b recessed along the recessed portion 74b, and adheres to the surface of the second connection pad 70b and the inner surface of the opening 72b (cover insulating layer 44d). In addition, the conductive adhesive Ad is adhered to the edge of the second cover layer 44e, and is blocked by the second cover layer 44e to limit the leakage to the drive wiring 45b side.

[0088] According to the head suspension assembly of the HDD of the third embodiment constructed as described above, in the mounting portion 60 of the flexure 40 on which the piezoelectric element 50 is mounted, by forming the first connection pad 70a and the second connection pad 70b in the recessed portions 74a and 74b formed in the base insulating layer 44b and setting the connection pads to be concave, the adhesive Ad can be fully accommodated and retained on the connection pads 70a and 70b. Therefore, even when the adhesive Ad is fully applied in a manner to avoid insufficiency in order to ensure the bonding strength and conductivity, the adhesive Ad can be prevented from wetting and spreading to the drive wiring side. In addition, on the first connection pad 70a side, a part of the conductive adhesive Ad flows on the cover insulating layer 44d and fills the recessed portion of the cover insulating layer 44d corresponding to the second recessed portion 74c. Since the cover insulating layer 44d is only formed overlappingly in the second recess 74c, the recess of the cover insulating layer 44d corresponding to the second recess 74c is formed deep, which can accommodate more adhesive, and the adhesive can be blocked by the side wall of the recess. Therefore, even if more conductive adhesive Ad is filled on the side of the first connecting pad 70a, it is possible to prevent the adhesive Ad from wetting and spreading to the drive wiring side. At the same time, the contact area between the adhesive Ad and the connecting pads 70a and 70b and the contact area between the adhesive Ad and the cover insulating layer 44d are increased, and a significant anchoring effect based on the recess can be obtained. As a result, the bonding strength of the adhesive Ad relative to the connecting pad is further improved.

[0089] Furthermore, on the second connection pad 70b side, the conductive adhesive Ad can be blocked by the second cover layer 44e functioning as a bank, thereby preventing the conductive adhesive Ad from leaking to the drive wiring 45b side.

[0090] By doing so, electrical short circuits and mechanical influences caused by the wetting and spreading of the conductive adhesive can be eliminated, thereby improving product yield. In this embodiment, a head gimbal assembly and a disk device having high connection strength of the piezoelectric element and improved reliability can be obtained.

[0091] (Fourth embodiment)

[0092] Fig.12 is a top view of a mounting portion on which a piezoelectric element is mounted in a head gimbal assembly according to a fourth embodiment. Fig.13 It is along Fig.12 A cross-sectional view of the mounting portion and the piezoelectric element along line DD.

[0093] As shown in the figure, in the mounting portion 60 of the flexure 40, in one example, the conductive layer 44c has a rectangular first connection pad 70a and an elongated strip-shaped drive wiring 45b connected to the first connection pad 70a. According to the present embodiment, the drive wiring 45b integrally has a pair of extensions 45c extending from the drive wiring 45b in two directions in the width direction and in the direction of the first connection pad 70a. These extensions 45c are spaced apart from one side edge of the first connection pad 70a and face each other. Thus, recesses 45d are formed between each extension 45c and one side edge of the first connection pad 70a and on both sides of the width direction of the drive wiring 45b.

[0094] In addition, the extension portion 45c is not limited to a strip shape or a straight line shape, and may be a curved shape or a coil-like shape.

[0095] The cover insulating layer 44d is stacked on the base insulating layer 44b in such a manner as to overlap the recessed portion 45d and the drive wiring 45b. In the cover insulating layer 44d, a region overlapping the recessed portion 45d is recessed along the recessed portion 45d to form a recessed portion. In the cover insulating layer 44d, a region overlapping the drive wiring 45b and the extension portion 45c is formed with a convex portion relative to the recessed portion 54d. The convex portion functions as a dam that restricts the spread of the conductive adhesive.

[0096] In the third embodiment, the second cover layer 44e on the first connection pad 70a side is omitted. The other structures of the mounting portion 60 are the same as those of the mounting portion 60 in the first embodiment described above.

[0097] The piezoelectric element 50 is arranged on the mounting portion 60 in a state where one end (first electrode 51a) of the piezoelectric body 50a in the longitudinal direction is opposite to the first connection pad 70a and the other end (second electrode 51b) in the longitudinal direction is opposite to the second connection pad 70b. A conductive adhesive Ad is filled between the first connection pad 70a and the first electrode 51a. The first electrode 51a is electrically and mechanically connected to the first connection pad 70a through the conductive adhesive Ad. At this time, the conductive adhesive Ad is filled into the opening 72a of the cover insulating layer 44d and the concave portion of the first connection pad 70a along the concave portion 74a, and adheres to the surface of the first connection pad 70a and the inner surface of the opening 72a (cover insulating layer 44d). A part of the conductive adhesive Ad flows on the cover insulating layer 44d and fills into the concave portion of the cover insulating layer 44d corresponding to the concave portion 45d. At the same time, the conductive adhesive Ad is blocked by the convex portion of the cover insulating layer 44d overlapping the extending portion 45c, thereby limiting leakage to the driving wiring 45b side.

[0098] A conductive adhesive Ad is filled between the second connection pad 70b and the second electrode 51b. The second electrode 51b is electrically and mechanically connected to the second connection pad 70b through the conductive adhesive Ad. The conductive adhesive Ad is filled into the opening 72b of the cover insulating layer 44d and the recessed portion of the second connection pad 70b recessed along the recessed portion 74b, and adheres to the surface of the second connection pad 70b and the inner surface of the opening 72b (cover insulating layer 44d). In addition, the conductive adhesive Ad is adhered to the edge of the second cover layer 44e, and is blocked by the second cover layer 44e to limit the leakage to the drive wiring 45b side.

[0099] According to the head suspension assembly of the HDD of the third embodiment constructed as described above, in the mounting portion 60 of the flexure 40 on which the piezoelectric element 50 is mounted, by forming the first connection pad 70a and the second connection pad 70b in the recessed portions 74a and 74b formed in the base insulating layer 44b and setting the connection pads to be concave, the adhesive Ad can be fully contained and retained on the connection pads 70a and 70b. Therefore, even when the adhesive Ad is fully applied in a manner to avoid insufficiency in order to ensure the bonding strength and conductivity, the adhesive Ad can be prevented from wetting and spreading to the drive wiring side. In addition, on the side of the first connection pad 70a, a concave-convex portion can be formed in the cover insulating layer 44d by the extension portion 45c extending from the drive wiring 45b, and a part of the conductive adhesive can be filled and contained in the concave portion. At the same time, the conductive adhesive can be blocked by the convex portion to limit the overflow of the adhesive to the drive wiring side.

[0100] Thus, according to the fourth embodiment, electrical short circuits and mechanical influences caused by the wetting and spreading of the conductive adhesive can be eliminated, thereby improving product yield. In this embodiment, a head gimbal assembly and a disk device having high connection strength of the piezoelectric element and improved reliability can be obtained.

[0101] The present invention is not limited to the above-mentioned embodiments as it is, and the constituent elements can be deformed and concretized in the implementation stage without departing from the scope of its purpose. In addition, various inventions can be formed by appropriate combinations of multiple constituent elements disclosed in the above-mentioned embodiments. For example, some constituent elements can also be deleted from all the constituent elements shown in the embodiments. Moreover, the constituent elements in different embodiments can also be appropriately combined.

[0102] For example, in the above-mentioned embodiment, a pair of piezoelectric elements 50 is provided as a structure installed on the universal joint portion 36 and located at the base end side of the load beam 35 relative to the magnetic head 17, but it is not limited to this. A pair of piezoelectric elements, for example, can also be arranged on both sides of the width direction of the support portion (tongue portion) supporting the magnetic head, and arranged in alignment with the magnetic head. The piezoelectric element is not limited to a pair, for example, a single piezoelectric element can also be used. The connection pad is not limited to a rectangular shape, and various shapes such as an ellipse, a circle, and a polygon can be selected.

Claims

1. A head suspension assembly comprising: Support plate; a wiring member disposed on the support plate; A head mounted on the wiring member; and a piezoelectric element mounted on the wiring member and capable of expansion and contraction, The wiring member comprises: a metal plate fixed to the support plate; and A laminated structure comprising a first insulating layer, a conductive layer laminated on the first insulating layer, a second insulating layer laminated on the first insulating layer and the conductive layer, at least one pair of connection pads formed by the conductive layer, and a plurality of wirings connected to the connection pads, The connection pad is provided so as to overlap with the concave portion formed in the first insulating layer, and a concave portion is formed which is sunken along the concave portion. The second insulating layer has an opening facing the connection pad, The piezoelectric element is connected to the connection pad by a conductive adhesive filled in the opening and the recess of the connection pad. The first insulating layer has second recesses arranged in a manner spaced apart from the recesses. The conductive layer and the second insulating layer are stacked in an overlapping manner in the second recessed portion, A portion of the conductive adhesive is filled in a recessed portion formed in the second insulating layer along the second recessed portion.

2. The head suspension assembly according to claim 1, The wiring member includes a second cover layer which is provided in an overlapping manner on the second insulating layer near the second recess and blocks the conductive adhesive.

3. A head suspension assembly comprising: Support plate; a wiring member disposed on the support plate; A head mounted on the wiring member; and a piezoelectric element mounted on the wiring member and capable of expansion and contraction, The wiring member comprises: a metal plate fixed to the support plate; and A laminated structure comprising a first insulating layer, a conductive layer laminated on the first insulating layer, a second insulating layer laminated on the first insulating layer and the conductive layer, at least one pair of connection pads formed by the conductive layer, and a plurality of wirings connected to the connection pads, The connection pad is provided so as to overlap with the concave portion formed in the first insulating layer, and a concave portion is formed which is sunken along the concave portion. The second insulating layer has an opening facing the connection pad, The piezoelectric element is connected to the connection pad by a conductive adhesive filled in the opening and the recess of the connection pad. The first insulating layer has second recesses arranged in a manner spaced apart from the recesses. The conductive layer is stacked on the first insulating layer at a position offset from the second recessed portion, The second insulating layer is stacked on the first insulating layer and the conductive layer so as to overlap the second recessed portion. A portion of the conductive adhesive is filled in a recessed portion formed in the second insulating layer along the second recessed portion.

4. A head suspension assembly comprising: Support plate; a wiring member disposed on the support plate; A head mounted on the wiring member; and a piezoelectric element mounted on the wiring member and capable of expansion and contraction, The wiring member comprises: a metal plate fixed to the support plate; and A laminated structure comprising a first insulating layer, a conductive layer laminated on the first insulating layer, a second insulating layer laminated on the first insulating layer and the conductive layer, at least one pair of connection pads formed by the conductive layer, and a plurality of wirings connected to the connection pads, The connection pad is provided so as to overlap with the concave portion formed in the first insulating layer, and a concave portion is formed which is sunken along the concave portion. The second insulating layer has an opening facing the connection pad, The piezoelectric element is connected to the connection pad by a conductive adhesive filled in the opening and the recess of the connection pad. The wiring member includes a second cover layer which is provided in an overlapping manner on the second insulating layer near the opening and blocks the conductive adhesive.

5. A head suspension assembly comprising: Support plate; a wiring member disposed on the support plate; A head mounted on the wiring member; and a piezoelectric element mounted on the wiring member and capable of expansion and contraction, The wiring member comprises: a metal plate fixed to the support plate; and A laminated structure comprising a first insulating layer, a conductive layer laminated on the first insulating layer, a second insulating layer laminated on the first insulating layer and the conductive layer, at least one pair of connection pads formed by the conductive layer, and a plurality of wirings connected to the connection pads, The connection pad is provided so as to overlap with the concave portion formed in the first insulating layer, and a concave portion is formed which is sunken along the concave portion. The second insulating layer has an opening facing the connection pad, The piezoelectric element is connected to the connection pad by a conductive adhesive filled in the opening and the recess of the connection pad. At least one wiring connected to the connection pad integrally includes an extension portion extending from the wiring and facing one side edge of the connection pad at a distance. The second insulating layer is stacked on the first insulating layer so as to overlap the wiring and the extending portion. A part of the conductive adhesive is filled in a recessed portion formed in the second insulating layer along a recessed portion between the extending portion and the connection pad.

6. A disk device comprising: a disk-shaped recording medium having a magnetic recording layer; and A head suspension assembly according to any one of claims 1 to 5 for supporting a magnetic head.

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